1. Field
The present invention relates to a terminal device, and an authentication server using position information for authentication.
2. Description of the Related Art
Conventionally, an authentication system has been disclosed in which a server authenticates a portable information terminal on the basis of position information received from the portable information terminal and provides an on-line business transaction service to the portable information terminal on the condition that the authentication result is affirmative. When the owner of the portable information terminal registers, for example, the owner's home or work place as an area where the authentication result becomes affirmative, the owner can use an on-line business transaction service without complicated operation including password entry. Also, even if the portable information terminal is missing or stolen by a third party, since the server will request the portable information terminal to transmit a password so long as the portable information terminal is positioned in an area where the authentication result is negative, illegal use of the on-line business transaction service can be prevented. (See Patent Document 1, for example.)
[Patent Document 1] Japanese Patent Application Laid-open No. 2002-232955
However, with the technique disclosed in the Patent Document 1, if the portable information terminal acquires position information from a Global Positioning System (GPS) satellite, for example, the position information may not be acquired when the portable information terminal is positioned indoors or in a basement where GPS satellite radio waves cannot easily reach, so that the server cannot perform authentication based on position information. Accordingly, users' convenience may be reduced.